Connectors are generally classified into plugs and Sockets in half.
Plugs generally refers to the fixed half. Plug plug with male contact; with negative contact of the plug receptacle. Sockets generally refers to the fixed (in the Panel or on the chassis) half. Male contact socket called socket socket called socket with negative exposure.
When plug in two when there is no distinction between fixed and not fixed (such as a cable connector), the contact form can be distinguished, says Plug connectors with male contact, with negative contact of the socket.
When plug in two no distinction between fixed and not fixed and no distinction between positive-negative with contacts, connectors for two and a half on both plugs and Sockets.
Four eyes: three-phase three-fire 103 eyes: wire, ground wire, zero two eyes: FireWire, left ground zero (n) fire on the right (l) to middle (PE)